1. Field of the Invention
This invention relates in general to communication systems and in particular to a spool for storing communications cable.
2. Description of the Related Art
Fiber optic cables are utilized in communications systems for carrying information between communication sources and sinks. An example of a communications system that utilizes fiber optic cable is an optical cross connect for a communications network.
Fiber optic cable typically includes at least one glass core for optical, high bandwidth transmission of information. Typically, fiber optic cable requires a minimum bending radius (e.g., a one-inch bending radius) to avoid damaging the glass core and to avoid producing a large dB loss in the transmission of information through the cable.
Improper handling of fiber optic cable during shipment and installation can damage the cable. Twists or kinks in the cable can cause microcracks, which over time can propagate in the cable and decrease the reliability and longevity of the system and result in costly field repairs and replacements.
Carriers are utilized in some communication systems for supporting fiber optic cable during manufacture, shipment and normal operation of a system. An example of a carrier is an 8xc3x978 perfect shuffle carrier which holds two sets of eight, 8-fiber ribbon cables where each fiber of each cable of the first set is optically coupled via an 8xc3x978 perfect shuffle optical flex circuit main body to a fiber of a cable of the second set to implement a perfect shuffle optical flex circuit. Such a shuffle may be implemented with splices that are held in the carrier. In one example, the splices are made in the factory to reduce expenses and manufacturing time and to assure quality. The splices and cable are then shipped in the carrier to a use location, where each cable is coupled to a communications circuit, such as a matrix card. To prevent damage to the cables during shipping, each cable is wrapped around a separate spool where cables enter and exit the spool in different rotational directions. Some spools include two circumferential pathways. The storage of the fiber must be accomplished in a small space while maintaining the required minimum bending radius.
What is needed is an improved technique for storing cable during shipping and during the operation of a communication system.
It has been discovered that providing a spool with an S shaped groove connecting two circumferential pathways advantageously provides an improved technique for managing cable during shipment, installation, and/or normal operation of a communication system.
In one aspect of the invention, an apparatus includes a spool defining a first circumferential cable pathway. The spool defines a second circumferential cable pathway. The spool defines an S shaped cable pathway extending generally through a middle region of the spool. The S shaped cable pathway connects the first circumferential cable pathway with the second circumferential cable pathway.
In another aspect the invention includes a method for rolling up excess fiber optic cable on a spool. The method includes placing a first portion of a fiber optic cable to be rolled up in an S shaped cable pathway of the spool extending from a first circumferential pathway of the spool to a second circuit pathway of the spool. The method also includes rotating the spool in a first direction wherein the rotation wraps a second portion of the fiber optic cable located on a first side of the first portion in the first circumferential pathway and wherein the rotation wraps a third portion of the fiber optic cable located on a second side of the first portion in the second circumferential pathway.
In another aspect of the invention, an apparatus including fiber optic cable also includes a carrier and a spool attached to the carrier. The spool defines a first circumferential cable pathway and a second circumferential cable pathway. The spool defines an S shaped cable pathway connecting the first circumferential cable pathway with the second circumferential cable pathway. The apparatus also includes a plurality of fiber optic cables secured to the carrier. Each cable of the plurality of cables includes an excess portion wound in the spool. A middle portion of the excess portion is located in an S shaped cable pathway. Each excess portion further includes a second portion located on a first side of the middle portion. The second portion is wound in the first circumferential cable pathway. Each excess portion further includes a third portion located on a second side of the middle portion. The third portion is wound in the second circumferential cable pathway.
In another aspect of the invention, a cable storage apparatus includes a spool defining a first circumferential cable pathway and a second circumferential cable pathway adjacent to the first circumferential cable pathway. The spool defines an interior cable pathway connecting the first circumferential cable pathway at a first location with the second circumferential cable pathway at a second location.
In another aspect of the invention, an apparatus includes a spool defining a first circumferential cable pathway and a defining a second circumferential cable pathway. The spool further includes means for connecting the first circumferential cable pathway with the second circumferential cable pathway such that a cable externally enters the first circumferential cable pathway in a same rotational direction as the cable externally exits the second circumferential cable pathway.